Answer
a) $C_{eq}=\frac{3}{5}C$
b) $Q_1=Q_2=\frac{1}{5}CV$
$Q_3=\frac{2}{5}CV$
$Q_4=\frac{3}{5}VC$
$V_1=V_2=\frac{1}{5}V$
$V_3=\frac{2}{5}V$
$V_4=\frac{3}{5}V$
Work Step by Step
a) $C_{1,2}=\frac{1}{\frac{1}{C_1}+\frac{1}{C_2}}$
$C_{1,2,3}=\frac{1}{\frac{1}{C_1}+\frac{1}{C_2}}+C_3$
$C_{eq}=\frac{1}{\frac{1}{C_4}+\frac{1}{\frac{1}{\frac{1}{C_1}+\frac{1}{C_2}}+C_3}}=\frac{3}{5}C$
b) $V=V_4=V_3=V_1+V_2$
$Q_1=Q_2$
$Q_1+Q_3=Q_4$
$Q_4=\frac{3}{5}VC$
$V_4=\frac{3}{5}V$
$V_{1,2,3}=\frac{2}{5}V=V_3$
$Q_3=\frac{2}{5}CV$
$Q_1=Q_2=C_{1,2}V_{1,2}=(\frac{1}{2}C)(\frac{2}{5}V)=\frac{1}{5}CV$
$V_1=\frac{Q_1}{C_1}=\frac{1}{5}V=V_2$
